Though
THOUGH, verb intransitive tho.
1. Grant; admit; allow. 'If thy brother be waxen poor--thou shalt relieve him; yea, though he be a stranger.' Grant or admit the fact that he is stranger, yet thou shalt relieve him. [[Leviticus 25#35|Leviticus 25:35]].
THOUGH he slay me, yet will I trust in him. [[Job 13#15|Job 13:15]].
That is, grant or admit that he shall slay me, yet will I trust in him.
THOUGH hand join in hand, the wicked shall not be unpunished. [[Proverbs 11#21|Proverbs 11:21]].
That is, admit the fact that the wicked unite their strength, yet this will not save them from punishment.
Not that I so affirm, though so it seem.
That is, grant that it seems so, yet I do not so affirm.
2. Used with as.
In the vine were three branches, and it was as though it budded. [[Genesis 40#10|Genesis 40:10]].
So we use as if; it was as if it budded; and if is gif, give. The appearance was like the real fact, if admitted or true.
3. It is used in familiar language, at the end of a sentence.
A good cause would do well though
This is generally or always elliptical, referring to some expression preceding or understood.